Who needs iPhone XC with LCD if there is iPhone XS with OLED?
If you can pay 600$ for XC, you can pay 800$ for XS too.
Its 200$.
Who cares?
Add $100 - $150 to your prices and you'll be in the ballpark. However, there are quite a few people who would like a larger phone for $200 less expensive and would be willing to give up AMOLED display and dual-lens camera to get it.
While I will admit most Americans are of the "what'll it cost me per month" mentality and there is a smaller segment that has money to burn and simply doesn't care what the price is as long as they get the best, there are still some of us who think long-term and realize that would be an extra $200 in our pocket with no real-world sacrifice in utility unless you really needed the better camera.
Of course, to you $200 apparently is nothing, but multiply that over other purchasing decisions like vehicles, furniture, appliances, clothing, dining out, etc. and you will find that being frugal while not sacrificing utility can result in very significant savings over one's lifetime.